Members called joints are often used to connect pressure sensors, flared copper pipes, and the like, to another piping and the like.
Incidentally, among such joints, a joint of which the connection portion can be sealed by deforming a metal gasket, such as a copper gasket is well known among persons skilled in the art (for example, refer to Japanese Patent Publication No. 2002-276866).
FIG. 1(a) depicts a representative example of such a joint. The joint 10 comprises a push rod 12, a main body 11, a steel ball 15, a spring 16, a copper gasket 13, and a copper pipe part 17, as depicted in FIG. 1(a).
The push rod 12 comprises a contact part 12a, a first passageway Pc11, and a second passageway Pc12. The contact part 12a is provided at one end part in the push rod longitudinal direction X. In addition, this contact part 12a is provided with a contact tapered part 12b. Furthermore, as is clear from FIG. 1(a), this contact tapered part 12b is provided at an end part of the contact part 12a on a push rod protruding side Xl in the push rod longitudinal direction X so that it surrounds the first passageway Pc11. In addition, the contact tapered part 12b is inclined toward the outer circumference and toward the opposite side X2 of the push rod protruding side in the push rod longitudinal direction X. Furthermore, when a male thread part 14 and a female thread part 22 of a pressure sensor connecting nut 20 depicted in FIG. 1(b) are screwed together in a state wherein the push rod 12 is housed in a push rod storage space SPc of the main body 11 which is discussed later, then the tapered part 12b contacts a nut tapered part 21 of the pressure sensor connecting nut 20 (refer to FIG. 1(b) and FIG. 1(c)). In addition, the end part of the push rod 12 on the opposite side X2 of the push rod protruding side in the push rod longitudinal direction X contacts the steel ball 15. Furthermore, the push rod 12 and the steel ball 15 are urged toward the push rod protruding side X1 in the push rod longitudinal direction X by a spring 16. Namely, when an external force is applied from the opposite side X2 of the push rod protruding side in the push rod longitudinal direction X, the push rod 12 is capable of moving along the push rod longitudinal direction X toward the opposite side X2 of the push rod protruding side. The first passageway Pc11 is formed along the push rod longitudinal direction X. In addition, the second passageway Pc12 is formed along a direction perpendicular to the push rod longitudinal direction X. Furthermore, the first passageway Pc11 and the second passageway Pc12 are in communication and form a first transit path Pc1.
The main body 11 comprises the push rod storage space SPc, the male thread part 14, and a second transit path Pc2. The push rod 12 is housed in the push rod storage space SPc so that the contact part 12a of the push rod 12 protrudes externally. Furthermore, the push rod storage space SPc, in a state wherein the push rod 12 is so housed, is in communication with the first transit path Pc1. The male thread part 14 is provided so that it surrounds the outer circumference of the push rod storage space SPc. Furthermore, the male thread part 14 is capable of screwing together with the female thread part 22 of the pressure sensor connecting nut 20 along the push rod longitudinal direction X (refer to FIG. 1(b)). The fluid that comes flowing from a fluid passageway of a copper piping (not shown) which is to be connected, flows to the second transit path Pc2.
The steel ball 15 is disposed in the second transit path Pc2 and urged by the spring 16, thereby separating between the push rod storage space SPc and the second transit path Pc2.
The spring 16 is disposed in the second transit path Pc2, the same as the steel ball 15, and urges the push rod 12 and the steel ball 15, as discussed above.
The copper gasket 13 is disposed in the space interposed between the surface of the contact part 12a on the opposite side X2 of the push rod protruding side in the push rod longitudinal direction X and the surface of the main body 11 on the push rod protruding side X1 in the push rod longitudinal direction X.
The copper pipe part 17 comprises a third transit path Pc3 and is connected to the lower end of the main body 11 by a solder 18. Furthermore, the lower end of the copper pipe part 17 is connected to the copper piping (not shown) by braising beforehand so that the passageway of the copper piping (not shown) to be connected and the third transit path Pc3 of the copper pipe part 17 are in communication.
Furthermore, to screw together the male thread part 14 of the joint 10 and the female thread part 22 of the pressure sensor connecting nut 20, the contact tapered part 12b first comes into contact with the nut tapered part 21 of the pressure sensor connecting nut 20, and the push rod 12 and the steel ball 15 then begin to move against the spring force of the spring 16 toward the opposite side X2 of the push rod protruding side in the push rod longitudinal direction X. As a result, a passageway Pp of the pressure sensor connecting nut 20 and a first transit path Pc1 of the push rod 12 communicate; additionally, the push rod storage space SPc and the second transit path Pc2 also communicate (refer to FIG.(c)). Furthermore, as the screwing together progresses, the copper gasket 13, which is deformed by being compressed by the surface of the contact part 12a on the opposite side X2 of the push rod protruding side in the push rod longitudinal direction X and the surface of the main body 11 on the push rod protruding side X1 in the push rod longitudinal direction X, seals the gap between the contact part 12a and the main body 11. In this state, the contact tapered part 12b and the nut tapered part 21 of the pressure sensor connecting nut 20 are sufficiently crimped, thereby sufficiently sealing the contact part 12a and the pressure sensor connecting nut 20.
In addition, the joint 10 is capable, in cooperation with a flared copper pipe connecting nut 40 depicted in FIG. 1(e), of connecting a flared copper pipe 30 depicted in FIG. 1(d) with another copper piping (not shown). Furthermore, the second transit path Pc2 of the joint 10 is connected to the fluid passageway of another copper piping (not shown) by braising, the same as in the case of the pressure sensor connecting nut 20. In addition, to connect the flared copper pipe 30 to the joint 10, the flared copper pipe 30 is inserted in advance into an opening HL of the flared copper pipe connecting nut 40 as depicted in FIG. 1(f). Furthermore, although a flared part 31 of the flared copper pipe 30 and a nut tapered part 41 of the flared copper pipe connecting nut 40 appear to be tightly sealed in FIG. 1(f), the flared part 31 of the flared copper pipe 30 and the nut tapered part 41 of the flared copper pipe connecting nut 40 are not necessarily tightly sealed in this state.
Furthermore, continuing with screwing together the male thread part 14 of the joint 10 and a female thread part 42 of the flared copper pipe connecting nut 40, the contact tapered part 12b first makes contact with the flared part 31 of the flared copper pipe 30, and then the push rod 12 and the steel ball 15 begin to move against the spring force of the spring 16 toward the opposite side X2 of the push rod protruding side in the push rod longitudinal direction X. As a result, a passageway Pf of the flared copper pipe 30 and a first transit path Pc1 of the push rod 12 communicate, and the push rod storage space SPc and the second transit path Pc2 also communicate (refer to FIG. 1(g)). Furthermore, as the screwing together progresses, the copper gasket 13, which is deformed by being compressed by the surface of the contact part 12a on the opposite side X2 of the push rod protruding side in the push rod longitudinal direction X and the surface of the main body 11 on the push rod protruding side X1 in the push rod longitudinal direction X, seals the gap between the contact part 12a and the main body 11. Furthermore, in this state, the flared part 31 of the flared copper pipe 30 is sufficiently pressed interposingly between the contact tapered part 12b and the nut tapered part 41 of the flared copper pipe connecting nut 40, thereby sufficiently sealing the flared part 31, the contact part 12a, and the flared copper pipe connecting nut 40.